1. Field of the Invention
The present invention relates to a sheet bundle binding processing apparatus which performs a binding process after collating and stacking image-formed sheets fed from an image forming apparatus, and relates to improvement of a binding processing mechanism capable of performing a binding process with one binding device selected from a plurality of binding devices.
2. Description of Related Arts
In general, there has been known a post-processing apparatus (finisher) which performs a binding process on sheets with images formed thereon by an image forming apparatus after collating and stacking the sheets on a processing tray. For performing a binding process, there have been known a stapling unit to perform a binding process using a staple, a press binding unit to bond overlapped sheets with pressing deformation, and a unit to bind a sheet bundle as forming an opening and a folding piece thereat.
A binding apparatus using a staple is known as an apparatus which reliably bonds a relatively thick sheet bundle as preventing the sheet bundle from being easily separated. Despite of a drawback of being easily separated, a press binding apparatus is used as a binding apparatus being environment-friendly with paper recycling and the like due to non-use of binding part such as a steel-made staple. Further, with such a binding apparatus, it has been known that the apparatus can be structured as being downsized, compactified, quiet, and power-saved.
Japanese Patent Application Laid-open No. 2011-190021 (FIGS. 1 and 3) discloses an apparatus which is continuously connected to a sheet discharging port of an image forming apparatus. Here, image-formed sheets are introduced to and stacked on a processing tray from an introducing path and a binding process is performed thereon, and then, the sheets are stored in a stack tray at the downstream side. Further, the sheet bundle fed and stacked to the processing tray from a sheet discharging path is positioned by being regulated with a tailing end in the sheet discharging direction abutted. In the above state, the sheet bundle is arranged on the processing tray to be capable of selecting a method from a method to perform a binding process (multi-binding) on a plurality of positions at the sheet tailing end with a stapling unit, a method to perform a binding process (corner binding) on a single corner position of the sheet bundle, and a binding method to perform a binding process without using a staple.
The staple-binding method is disclosed as a stapling unit and the non-staple binding unit is disclosed as a press binding unit. The stapling unit is supported by a guide rail to be movable along the end face of the sheet bundle positioned on the processing tray to perform multi-binding at a predetermined interval or corner binding at a single corner position. Further, the non-staple binding unit is structured to bond sheets mutually with pressing deformation using a binder mechanism having an upper-lower pair of corrugation-shaped pressurizing faces.
Further, Japanese Patent Application Laid-open No. 2012-025499 (FIG. 2) discloses a similar apparatus as disclosed above. Here, there is disclosed an apparatus in which sheets fed from an image forming apparatus are discharged to a stack tray at the downstream side, after a post-processing is performed thereon as selecting a binding process using a staple or a binding process with a non-staple binding unit in a state that the sheets are stacked on a processing tray.
Further, Japanese Patent Application Laid-open No. 2005-096392 (FIG. 3) discloses an apparatus including a stage arranged at a body casing, the stage having a slit-shaped groove to which a sheet bundle is inserted. Here, after sheets fed from an image forming apparatus are collated and stacked on a stack tray, an operator inserts the sheet bundle to the stage so that a binding process is performed thereon with a stapling unit arranged inside the body casing.